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IS ADDITIONAL WATER A FRIEND OR AN ENEMY?




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  7. C. Practice introducing yourself, friends and groupmates. Remember to smile (and use handshakes where appropriate).
  8. Consult the TEXTS FOR SUPPLEMENTARY READING and learn about early attempts to find or get clean water (Text 47). Be ready to discuss the information you have read.
  9. Consult the TEXTS FOR SUPPLEMENTARY READING and learn about the advent of municipal water treatment (Text 48). Be ready to discuss the information you have read.
  10. Exercise 6. Ask your friend all possible questions to the following sentences.

Master the key terms and head words.

achievement - достижение layer — слой

hydration - гидрация, присоеди- liquid — жидкость
нение воды ratio — отношение


specification — технические условия to cure — сохранять, исправлять»
vapour — испарение, пар выдерживать

124. Put down the corresponding verbs a) nouns b); translate the words.

Model: foundation - to found (a) to enrich - enrichment (b)

a) corrosion -to______ b) to enrich —__________ __^

hydration - to______ to require -____________

invention — to____ ____ to achieve —_____________

penetration -to________ to attach -______________

evaporation —to______ ____ to adjust —___________

relation — to_____

specification -to________

125. Read the combinations. Translate them from Russian.

covering material — материал покрытия

cover of roof — кровля

water/cement ratio — пропорция воды в растворе

concrete curing — выдержка бетона

compressive strength - сопротивление на сжатие

vapour pipe — паровой патрубок

vapour heating system — система парового отопления

126. a) Translate the given prepositions into English.

1. The cover zone is the layer (между)___ the steel reinforcement

and concrete surface.

2. The durability of cover zone depends (от)___ the mix design ctf

concrete.

3. (В течение)_________ the period of concrete curing, a minimum

of cement content and a maximum of water/cement ratio is include^
(в)_____ the mix.

4. Water is added (к)___ concrete (для)____ hydration of cement

5. Additional amounts of water increase the pores (в, внутри)__

the concrete's structure.

6. The process of concrete's curing lasts for (около)___ 28 days

b) Translate the examples into Russian. Mind Participle II.

1. ... additional amount of water poured into the mix...

2. ... required strength achieved with minimum cement content...

3. ... durability increased by adding water...

4. ... workability provided by the necessary amount of aggregates ...

5*



Essential Course


Unit Eight. Concrete



 


Read and translate the article.

One of the key requirements of concrete service is its durability. And the quality of cover zone (покрытие) is of primary importance for provid­ing concrete's durability. The cover zone is the concrete layer between the steel reinforcement and concrete surface. It should be taken into account that durability of concrete zone depends upon the mix design of concrete and the properties of the concrete itself.



The process of concrete's curing, as we know, lasts for about 28 days. And the compressive strength at 28 days is considered to be the basis of con­crete specification. During the period of curing, engineers frequently in­clude a minimum of cement (content) and a maximum of water/cement ratio into the mix.

Naturally, different construction purposes require different cement con­tent, and for many types of mixes the required strength can be achieved with the minimum cement content. Engineers add water to concrete for hydra­tion of cement. But the minimum amount of water needed for hydration of the mix may be too little to provide the necessary workability of the mix. So, in order to increase workability of concrete, additional amounts of water can be poured into the mix. And what is the result of this operation? It turns out that additional amounts of water increase the pores within the concrete's structure, especially after evaporation. It leads, in its turn, to an increase of gas, vapour, and liquid penetration into the structure of the mix. It is noted that especially strong this penetration is in the cover zone. So, one can see that additional water provides the potential for structural mix to decrease its durability. One more disadvantage of adding water to the concrete mix is its reinforcement corrosion and cracking. Additional corrosion and cracking provide new ways for gas, vapour, and liquids to penetrate into the cover zone. So, is additional water concrete's friend or enemy?




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